JPS6177037A - Magnification varying mechanism of copying machine - Google Patents

Abstract

PURPOSE:To vary magnification accurately with a simple structure by changing the position of a lens and moving a mirror by a cable, which is attached to a cam follower slided on a lens holder, to change the optical path length. CONSTITUTION:A drive pulley 27 is rotated forward or reverse by a motor omitted in the figure to move left or right an endless belt 28 stretched around following-up pulleys 25 and 26. A holder 14 of a lens 11 is moved in directions of arrows A and B in accordance with movement of the belt 28. A cam follower 31 connected to the lens holder 14 by an arm 30 is slided on a cam face 32' of a shake cam 32. When the lens holder 14 is moved in the direction of the arrow A or B, the shake cam 32 is shaked clockwise or counterclockwise around a shaft 33. A cable 34 attached to the shake cam 32 rotates a connection pulley 37 forward or reverse in accordance with shake to move forward or backward an endless belt 38 stretched around pulleys 35 and 36, and a mirror carriage 13 is moved forward or backward to change the optical path length. Thus, the magnification is varied accurately with one motor.

Description

[Detailed Description of the Invention] The present invention is capable of forming an image of a document on the exposure surface of a photoreceptor when a lens is moved and adjusted to a lens position that can match a predetermined copying magnification. The present invention relates to a variable magnification type copying machine that can move a mirror to a position required for copying.

” When performing continuous enlargement and reduction using a fixed focus lens,
It is necessary to adjust the position of the lens and the total optical path length between the document surface and the photoreceptor surface according to the magnification.

Therefore, in the past, two sets of motors J5 and a control bar were used to separately control the lens position and the total optical path length.

Another method is to convert the displacement of a rotating cam directly connected to the lens drive Jffi B'l into the movement of a mirror.

However, in the conventional example of a novice, by using two sets of motors and a control device (although the missing structure is somewhat simplified, the position control motor is high I). For this reason, the cost is high, and if a slight deviation occurs in either side, the image of the document cannot be clearly imaged on the exposed surface of the photoreceptor.

In the latter example, since the amount of movement required for the mirror is subtracted by 1q from the displacement of the rotary cam, it is necessary to use a rotary cam with a large diameter or to use a widening search structure that increases the displacement of the cam. When using a large diameter cam, it takes up more space,
The machine became larger, and the number of parts increased when the machine was made larger, and the number of parts increased, making it complicated and expensive.

The present invention has been made in view of the above, and an object of the present invention is to provide a variable magnification mechanism that uses a swinging cam of a specific shape to move a mirror a predetermined distance in conjunction with the movement of a lens. It is in the point of providing.

1" (I J@ for copying - and 1) The present invention operates a lens position @adjusting means to set a position in the optical axis direction of the lens corresponding to the copying magnification. The follower moves together with the lens, and the movement of the cam follower causes a cam with a special shape to swing, and the tension of the cable connected to the cam operates the mirror moving means, causing the mirror to move to a predetermined position J:. can do.

Therefore, when the lens position adjustment means moves the lens according to the double 77 magnification, the optical path length can also be set according to the 8 magnification by moving the mirror a predetermined distance in conjunction with this, and the image on the surface of the photoreceptor is always can be made clear.

Embodiments of the present invention illustrated in FIGS. 1 to 7 will be described below.

Reference numeral 1 denotes a slit exposure platen moving type dry electrophotographic copying machine, in which a platen glass 3 is provided above a casing 2 so as to be movable back and forth by a motor (not shown), and a platen cover 4 is provided above the glass 3. can be opened and closed freely (=J is closed).

Further, in the copying machine 1, an exposure run 16 is fixed below the platen glass 3, and a first mirror 7 is fixed to the left of the exposure run 16, and further to the left of the first mirror 7 (a second mirror 8 and a second mirror 7) are fixed. A third mirror 9 below the two mirrors 8 is integrally supported by a mirror carriage 13 so as to be movable left and right.

A lens 11 is mounted on the lens mount 1 on the right side of the third mirror 9.
A fourth mirror 10 is disposed on the right side of the fourth mirror 10, and the exposure lamp 6 is
The light that is projected by the original 5 on the platen glass 3 is reflected in sequence by the first, second, and third mirrors 7, 8, 9, passes through the lens 11, and is reflected by the fourth mirror 10. After that, the drum-shaped photoreceptor 12 is irradiated with the light.

A charger 15 and a developer 1 are provided on the outer periphery of the drum-shaped photoreceptor 12.
G, transfer device 17, peeler 18 and cleaning device 19
They are arranged sequentially around the hour 81 in Figure 2.

Furthermore, a paper tray 20 is arranged on the right side of the developing device 16.
The paper 21 stored in the same tray 20 is fed to the paper feeder 2.
After being sent to the drum-shaped photoreceptor 12 by 2 and transferred,
The image is sent to a fixing device 23, fixed thereon, and then ejected onto an ejection tray 24.

Next, to explain the magnification changing mechanism of the exposure system, the lens 11
A lens mount 14 supporting the lens is mounted on a lens guide rail (not shown) arranged horizontally along the front and rear walls so as to be movable to the right.

In addition, two pairs of pulleys 25.2G are supported in two places on the left and right above the lens guide rail. 21 is pivotally supported, and a JB cable 28 is wound around the same drive pulley 27, and is spanned over pulleys 25 and 26 in the opposite direction, and the Tanabata 29 is connected to the Dry 1 pulley 27. , same end cable 28 (Ulens mount 14
14 is moved left and right to the lens mount 1 by forward and reverse rotation of the motor 29 (J, .).

Further, on the lower surface of the lens mount 14, along the front and rear walls, 1
A pair of L-shaped cam follower arms 30 are fixed with their tips facing outward;
1 is pivoted.

The swing cam 32 is supported from below by the cam 40 wire 31, and is pivoted about the fixed @33 as a fulcrum, and one end of the cable 34 is tied to the end opposite to the pivot point. ing.

Further, the mirror carriage 13 that supports the second and third mirrors 8.9 is movably mounted on mirror guide rails (not shown) that are arranged horizontally along the front and rear walls. ing.

Two pairs of pulleys 35 and 36 are respectively pivotally supported at two left and right positions below the guide rail.
．． The connecting pulley 37 is pivotally supported so that the upper part of the connecting pulley 37 is in contact with the line connecting the lower part of the connecting pulley 36.
The endless cable 38 wound counterclockwise around the left pulley 35 is wound counterclockwise around the left pulley 35, and then wound counterclockwise around the right pulley 36, and is then wound around the connecting pulley 37 again. It is wound back counterclockwise.

Further, a cable 34 whose one end is tied to the swing cam 32 is wound counterclockwise around the connecting pulley 37 via pulleys 39 and 40, and its tip end is tied to the connecting pulley 37.

The connecting pulley 37 is always subjected to a force in the direction of pulling the cable 34 (counterclockwise in FIG. 1) by a spring (not shown).

The j♂ moving cam 32 has a specific shape with a needle valve as described later, and is concave toward the lower part of the human body, and as the cam follower 31 moves straight from side to side, it moves up and down. It swings to pull or loosen the glue 311.

When the cable 34 is pulled, the connecting pulley 37' rotates clockwise, and the mirror carriage 13 is moved to the left by the endless cable 38. Conversely, when the cable 34 is loosened, the connecting pulley 37' rotates clockwise. Miraki V Ridge 13
is moved to the right.

Therefore, by driving the motor 29 that moves the lens 11, the second. The third mirror 8.9 will also be moved at the same time.

The movement of the lens 11 is adjusted appropriately according to the copying magnification set by the control device that controls the motor 29, and the movement of the second and third mirrors 8.9 (5jJΦ) is controlled by the cam device. must be used to convert it into a given a.

The shape of the swing cam for this purpose will be explained below.

Now let α be the optical path length from the surface of the original to the lens, β be the optical path length from the lens to the surface of the photoreceptor, let f be the focal length of the lens, WJ, and m the magnification. Since the position of the body surface is fixed, the optical path length β to the lens and the optical path length A (= α + β) to the document surface can be expressed as a function of the copying rate m, based on the exposed surface of the photoreceptor surface, and so on. The amount of change from the double time (β=2f, J=4f) is as shown in the following equation.

γ - (1 - m) f ... (1) δ - construction soil 22 double f ... (2) Therefore, the copying magnification m is set, and the lens 11 is moved by γ from the position at the same magnification. In this case, the first mirror and the third mirror 8.9 are moved by δ/2. This is because when the second and third mirrors 8.9 move by δ/″2, the optical path length changes by δ.

The extended part of the cam device is shown in FIG. The state at the time of η times is shown by a solid line, and there is a connection ('+ IA P) of the cable 34 at a distance a from the fulcrum O in the left horizontal direction, and the cable 34 runs vertically from the same point P, and the cable 34
A pulley 40 is arranged so as to be in contact with. Let the contact point be t(t), and the distance it p H be b.The pulley 40 has a center point Q and a radius r, !, :i'.

Here, if we take the orthogonal coordinate axes J and urchin in the figure with the fulcrum 0 as the origin, the respective coordinates of P, Q, 1'' are PC-fl, o),
Q(-a-r, -b), l-1(-a, -b).

The broken line shows the state when the swing cam 32 has rotated clockwise by θ (rad), and the 1 point and 1-1 point after movement are P'
point, H' point, P' point is (-a cos θ.

a sin θ), and point H' is at the position (-a-r
(1-cosφ), -br sinφ).

Equation of tangent to circle Q at Todo point (-a-r (1-cosφ)+a+r) (×+a+r
)←(J-r sinφ +1+)(V+b) =
r”, rearranging the formula, CO3φ(x+a+r)−sinφ(y4b)=r
=-(3).

Since the straight line shown by this equation (3) passes through point P', COS
φ(−a cosθ+a+r) −sinφ(a sinθ+b)=r −=(4)
The formula holds true.

Next, since the rocking cam 32 rotated by θ (rad), the state ΔL in which the cable extends is -j7 - (vinegar + Ω') = (a + r - a cos θ) ' + (a sin
θ+b)2-r-(b+rφ), and since this ΔL is the first and second mirrors 8, (a+r-fl CO3θ)'(a 5inQ+t+
) −r −(b+rφ) holds true.

therefore? ! 2 shots (when 8 rate m is set, (4),
From equation (5), θ and φ are determined.

Kamuf A1. ．． Assuming that the T I no 31 moves left and right so as to be in contact with the straight line FiIr'o, the curve representing the cam shape is at a position that is in contact with the straight line PO at the same magnification.

Therefore, among the contact points, the equal 18 o'clock point is 5 (-C, O
), and the contact point when the copying magnification is m is S' point, (
From equation 1), the 8 motion 9 from 18:00 becomes (1-m) f, which becomes TeS-(-C+(1-m)(0).

Now, the cam shape at the same magnification is 1, the I:f: point of the curve (solid line) is R (X, Y), and the same point θ (rad
) If the point after rotation is R'(X',Y'), then
Between (X, Y) and (X', Y') (YoX=X'
A relationship such as cosθ−Y′sinθ Y=X′sinθ+y′cO3θ holds true.

Here, assuming that R'(X',Y') satisfies the point S', the following equation holds true.

X= f−C+ (1−m)f) cosθ ・(6)Y
= (-C+ (1・-m) f ) sinθ・(
7) This (X, Y) represents the curve showing the cam shape, and from the copy jf54 < m and the same magnification m, (4), (51
From the +iff notation θ found using the formula, (6), (
7) The point (X, Y) on the curve is determined by the equation.

If you actually measure the teaching value and represent it in a diagram, it will look like Figure 5.

Here r=270 (mm), a=220 (mm1.
b=100<mm), C=110(mm), r=
It is assumed to be 10 (mm).

Note that θ can be found by solving equations (4) and (5) from double fm, since the 81 bell is tilted, so by calculating m backwards from θ, some of the curves (X, Y) showing the cam shape can be obtained. If you set the point to 0, the result will be as shown in the table below.

Figure 5 shows the coordinates of these 31 results.

For example, when copying (7r, magnification rate m = 11) is set, the cam follower 31 moves from position 12 (from position 12) to I horn 108 (=: N-m) r l = l (1-
14) x 270 l) mm is avoided, and the movement of the horizontal direction r\ of the Jmufu 40 31 is avoided. ・FJJ rotates the 1st moving cam 32 around the time of 51 about 1/1 (J), so the Kasol 3
4 is stretched by about 15.43 mm from the original size, and the 2nd. The third mirror 8.9 moves to the left and the copy magnification is 1.
4 exposure system settings are made.

On the other hand, in the case of reduced copying, the lens + 1 + is more than the muff 4 [1 w =
31 and to the right, and the first moving cam 32 similarly swings clockwise, so the second moving cam 32 moves clockwise. The third mirror 8.9 is moved to the left, and the exposure system is set.

As is clear from FIG. 5, the cam shape has a smooth curve as a whole, and there are no steep parts, so there is no strain on the drive system.

Note that in this embodiment, the second. The third mirror 8.9 was moved via two pairs of pulleys 35, 36 and an endless cable 38° connecting pulley 37, but one end of the cable 34 connected from the swing cam 32 was used directly. 3rd mirror 8.9
It is also possible to simplify the mechanism by attaching a stone to the mirror gear ridge 13 on which the mirror gear ridge 13 is mounted, and making it movable to the left via a boot, and always being pulled in the right direction by a spring or the like.

31. As shown in FIG. 6, the present invention is also applicable to a method of copying in which the second and third mirrors 8 and 9 of the above embodiment are not provided, and light is sent from the first mirror to the zero-contact lens. As shown in the figure, the cable 34 whose one end is tied to the swing cam 32 is tied to the mirror carriage 42 of the first mirror 7 via the pulley 41, and as the lens 11 moves, the first
In this case, the moving ink C,↓n of the first mirror 7 becomes δ, unlike δ/2 in the embodiment I, in this case. The amount of change in r)' optical path L: remains unchanged. In this method, the star 1 position of the platen becomes the stomach by the 18 rate.

In addition, in this embodiment, platen movement +51117) return'7
11.1 can be applied to the 71st generation during copying when the optical system moves ψ, and 114j in that case
Figure 7 shows you.

In the figure, the optical path length adjustment pulley 35.3G and the connecting pulley 37 are arranged in the same positional relationship as in the above embodiment,
Upper side of pulley J5*U6←>12 (J2) Pulleys 44 and 45 are arranged on the sweat G so as to be in contact with the upper horizontal tangent of the pulley 43.

The cable 46, which is wound one turn counterclockwise around the connecting pulley 37, is wound around the left pulley 35 for optical path length: JJp for half a turn in the hour δ1 direction, and then wound around the movable pulley 13 in the counterclockwise direction. Winding a half turn (after being pulled, the left pulley 44 is wound half a turn counterclockwise, and then the right pulley 45
is wound counterclockwise for half a turn, and then the movable pulley 4
After FA, the endless cable 46 is wound around the right optical path length adjustment pulley 36 for a half turn clockwise, and then returned to the connecting pulley 37.
are bridged over pulleys 35, 36, 37, 43 degrees 44 and 45 one after another.

An exposure lamp 6 and a first mirror 7 are integrally attached to a cable 46 between the pulley 45 and the movable pulley 43.

Since I am using the above fM) Pi, i! When the pulley 44 is rotated in the opening direction or the closing direction with the 13-coupling pulley 37 fixed, the exposure lamp 6 and the first mirror 7 move left and right, and the second... Third mirror 8
．． 9 moves left and right at half the speed, and keeps the optical path length constant during exposure scanning.

Further, when the connecting pulley 37 is rotated clockwise or counterclockwise while the rotation of the pulleys 26 and 27 is fixed, the second. The third mirror 8.9 can be moved to the left or right to change the optical path length.

J-3 In this case, the amount of movement of the second and third mirrors 8 and 9 is half of the movement of the cable 34 in the above embodiment in which the connecting pulley 37 is rotated ll+,i;sl,). Therefore, the amount of cable movement for the set copying magnification m is given by equation (2) above, δ(=(I and m)' r
).

As described above, the present invention can be applied not only to one-platen multi-sensor type copying (not only to multi-platen type copying but also to optical system moving type copying).

Le J1 and Kuri In this way, the present invention uses one motor to simultaneously change the lens position and optical path length. Therefore, assuming that the image placed on the surface of the photoreceptor is always clear, 1JIi is also less expensive.

In addition, the cam shape has an almost smooth curve 111, Z.

Since there are no steep parts, there is no stress on the cam follower,
There is no burden on the motor.

Furthermore, by increasing the length of the cam, it is possible to set a wide range of copying magnifications for enlargement and reduction.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view of an embodiment of the copying machine according to the present invention, showing the same size copy state, Fig. 2 shows the reduced copy state, and Fig. 3 shows the same 18 FIG. 4 is a schematic diagram of the main parts of the cam device for ejecting the cam shape, FIG. 5 is a diagram showing the cam shape calculated by the needle bar, and FIG. 6 is another embodiment. FIG. 7 is a diagram showing an example of the application of the present invention in FIG. 7, and FIG.

Claims (1)

[Claims] In a variable copy magnification type copying machine that can change the copy magnification by changing the position of the lens and mirror without changing the focal length of the lens, the position of the lens in the optical axis direction can be changed in accordance with the copy magnification. A lens position adjustment means, a cam follower integrated with the means for supporting the lens, a cam that swings around a fixed axis by movement of the cam follower, and a mirror that moves its position in the optical axis direction. a mirror moving means that can change the optical path length by moving the cam; and a cable that connects the cam and the mirror moving means and transmits motion so that the rocking motion of the cam can be used to move the mirror. 1. A variable magnification mechanism for a copying machine, characterized in that the shape is formed to convert the amount of movement of a lens in accordance with a copying magnification into the amount of movement of a mirror in accordance with the copying magnification.